Improvement in twin stairs, elevators, and light-shafts



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S. GRAY. r TWINSTAIRS ELEVATORS AND LIGHT SHAFT.

No.174,519. Patented March 7,1876.

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- TWIN STAIRS ELEVATORS AND LIGHTSHAFT.

No.174,519. Patented March 7,1876.

` Izwizwf/ N.F'ETERS. PNETN'LLITNDGFKAPHERl WASHINGTON, B C.

UNITED STATES PATENT OFFICE SAMUEL GRAY, oF sAN FRANCISCO, CALIFORNIA.

IMPROVEMENT IN TWIN STAIRS, ELEVATORS,AND LIGHT-SHAFTS.

Specification forming part of Letters Patent No. 174,519, dated March 7,1876; application filed November 17,1875.

To all whom it may concern:

Be it known that I, SAMUEL GRAY, of San Francisco, in the State of California, have invented certain new and useful Improvements in the Construction and Arrangement of Twin Stairs, Elevator, and Light-Shaft, oi' which the following is a specification:

The object of my invention is to secure perfecit safety, combined. with beauty and comfort, by the construction oftwin stairs, elevator, and light-shaft combined, and to economize space, so as to require no more than that required for, the ordinary well-hole for spiral stairs, thus adapting it to those already constructed without cutting or destroying any part of the building except the basementloor. v i

The following is the construction of the same: The stairs are made self-supporting,

stringer, as well as at the bottom. The inside' line of the stringere being of steeper ascent than the outside Stringer, and being of the same width, a perpendicular line across the same is longer; hence the inside ot' the attachment of the riser is broader than that to the outside strin ger, 'giving the effect of a bracket, and giving superior strength to the structure .l ofthe stairs.

It will be seen that the space occupied by the twin stairs is no more than that required for a single iiight of spiral stairs, and a great advantage is secured in avoiding the obstruction caused by having to ascend and descend upon the same iiight of stairs. The elevator is operated by four perpendicular screws, which operate in the platformior frame which supports the same. l

The following is the operation of the same: The driving-shaft I being revolved by a small engine or other suitable motive power, motion is given to the screws F by means of the bevelgear J and K and the spur gear L. The guardsleeves M have mortises, through which the hangers N project, which hold the journals 0 of the screws F, and have an inner slot running the whole length, to allow the connection with the elevator and the same to move up and down. P is the light-shaft.

The advantages of my invention are seen in the economy of space, in beauty of construction, in pleasantness, being well lighted and airy, and perfectly safe, as it avoids all accidents so common to the elevators of ordinary construction.

lt will be seen that it is best to place thev braces on hangers N, which support the journals of the screws at different heights, so as to secure the bearing of the full thread of at least half of the screws at all times, and while the others are being passed by the female screws at their journals O. A different number of screws may be used to operate the elevator; but I. find four to be the best number and more convenient in practical working.

4The light and Ventilating shaft P is constructed by throwing an extra c vlinderyaround and concentric with the stair-cylinder, with space between to admit sufficient light and for-ventilation. The light-shaft ex'tends around'the well-hole, except at the landings R, where the elevator-car is entered at each floor.

.P, the whole being constructed and operated substantially as and for the purposes set forth.

SAMUEL GRAY. Witnesses:

J CEN H. REDsToNE, ALBERT E. REDsToNE. 

